Modulating Brain Activity with Invasive Brain-Computer Interface: A Narrative Review

Abstract

Brain-computer interface (BCI) can be used as a real-time bidirectional information gateway between the brain and machines. In particular, rapid progress in invasive BCI, propelled by recent developments in electrode materials, miniature and power-efficient electronics, and neural signal decoding technologies has attracted wide attention. In this review, we first introduce the concepts of neuronal signal decoding and encoding that are fundamental for information exchanges in BCI. Then, we review the history and recent advances in invasive BCI, particularly through studies using neural signals for controlling external devices on one hand, and modulating brain activity on the other hand. Specifically, regarding modulating brain activity, we focus on two types of techniques, applying electrical stimulation to cortical and deep brain tissues, respectively. Finally, we discuss the related ethical issues concerning the clinical application of this emerging technology.

Keywords: BCI; DBS; ICMS; decode; encode; invasive; modulate.

Figure 1

The progression of invasive BCI. (A). The number of published papers over time. A rapid growth in the number of papers in recent (20) years demonstrates the rapidly increasing interest in invasive BCI technology. (B). The historical timeline for major breakthroughs and representative developments in invasive BCI. The references cited in a–k correspond to the following: a [5], b [6], c [7,8], d [9], e [10], f [11,12,13,14], g [15], h [16], i [17], j [18], and k [19].

Figure 2

Applications of decoding. The application of decoding is a process from recording electrical signals of brain activity, such as spikes and LFPs, to using them to control external devices.

Figure 3

ICMS in restoring tactile sensation and vision. (a) ICMS with the microelectrode array in the primary somatosensory cortex can evoke tactile sensation of hand. The left colorful square represents the microelectrode array and the color is the ICMS area relative to tactile sensation of the hand area with the same color; (b) ICMS with microelectrode array in the visual cortex can help patients to identify some letters and object boundaries. The left square represents the microelectrode array and the blue rhombus within it represents the ICMS area, which relates to the optical illusion.

Figure 4

Framework and clinical application of DBS. Framework and clinical application of DBS. The blue bag represents the pulse generator and the stick in brain tissue represents electrode of DBS.